Recent organic matter accumulation in relation to some climatic factors in ombrotrophic peat bogs near heavy metal emission sources in Finland     

L. Ukonmaanaho  T.M. Nieminen  N. Rausch  A. Cheburkin  G. Le Roux  W. Shotyk 《Global and Planetary Change》2006,53(4):259

Accumulation of organic matter (OM) was studied in four ombrotrophic peat bogs in Finland: Harjavalta (vicinity of a Cu–Ni smelter), Outokumpu (near a closed Cu–Ni mine), Alkkia (Ni-treated site) and Hietajärvi (a pristine site). At each sampling site, two peat cores (15 × 15 × 100 cm) were taken. Age-dating of peat was determined using ²¹⁰Pb method (CRS model). The local annual temperature sum and precipitation for the past 125 years were modeled. The objective was to compare recent net accumulation rates of heavy metal polluted ombrotrophic peat bogs with those of a pristine bog, and to study the relationship between weather and net accumulation rates. Based on ²¹⁰Pb age-dating, the upper 16-cm peat layer at Harjavalta, 35 cm at Outokumpu and 25 cm at Hietajärvi represents 125 years of peat formation, yielding the following average peat accumulation rates: Harjavalta 1.3 mm year^− 1, Outokumpu 2.8 mm year^− 1 and Hietajärvi 2.0 mm year^− 1. At the Alkkia site, the Ni treatment in 1962 had completely stopped the peat accumulation. Net accumulation rates were related to precipitation at Outokumpu, Harjavalta and Hietajärvi sites. In addition, emissions released from the nearby located Cu–Ni smelter could have affected negatively net OM accumulation rate at Harjavalta site.  相似文献   

The electron–cyclotron maser for astrophysical application     

Rudolf A. Treumann 《Astronomy and Astrophysics Review》2006,13(4):229-315

The electron–cyclotron maser is a process that generates coherent radiation from plasma. In the last two decades, it has gained increasing attention as a dominant mechanism of producing high-power radiation in natural high-temperature magnetized plasmas. Originally proposed as a somewhat exotic idea and subsequently applied to include non-relativistic plasmas, the electron–cyclotron maser was considered as an alternative to turbulent though coherent wave–wave interaction which results in radio emission. However, when it was recognized that weak relativistic corrections had to be taken into account in the radiation process, the importance of the electron–cyclotron maser rose to the recognition it deserves. Here we review the theory and application of the electron–cyclotron maser to the directly accessible plasmas in our immediate terrestrial and planetary environments. In situ access to the radiating plasmas has turned out to be crucial in identifying the conditions under which the electron–cyclotron maser mechanism is working. Under extreme astrophysical conditions, radiation from plasmas may provide a major energy loss; however, for generating the powerful radiation in which the electron–cyclotron maser mechanism is capable, the plasma must be in a state where release of susceptible amounts of energy in the form of radiation is favorable. Such conditions are realized when the plasma is unable to digest the available free energy that is imposed from outside and stored in its particle distribution. The lack of dissipative processes is a common property of collisionless plasmas. When, in addition, the plasma density becomes so low that the amount of free energy per particle is large, direct emission becomes favorable. This can be expressed as negative absorption of the plasma which, like in conventional masers, leads to coherent emission even though no quantum correlations are involved. The physical basis of this formal analogy between a quantum maser and the electron–cyclotron maser is that in the electron–cyclotron maser the free-space radiation modes can be amplified directly. Several models have been proposed for such a process. The most famous one is the so-called loss-cone maser. However, as argued in this review, the loss-cone maser is rather inefficient. Available in situ measurements indicate that the loss-cone maser plays only a minor role. Instead, the main source for any strong electron–cyclotron maser is found in the presence of a magnetic-field-aligned electric potential drop which has several effects: (1) it dilutes the local plasma to such an extent that the plasma enters the regime in which the electron–cyclotron maser becomes effective; (2) it generates energetic relativistic electron beams and field-aligned currents; (3) it deforms, together with the magnetic mirror force, the electron distribution function, thereby mimicking a high energy level sufficiently far above the Maxwellian ground state of an equilibrium plasma; (4) it favors emission in the free-space RX mode in a direction roughly perpendicular to the ambient magnetic field; (5) this emission is the most intense, since it implies the coherent resonant contribution of a maximum number of electrons in the distribution function to the radiation (i.e., to the generation of negative absorption); (6) it generates a large number of electron holes via the two-stream instability, and ion holes via the current-driven ion-acoustic instability which manifest themselves as subtle fine structures moving across the radiation spectrum and being typical for the electron–cyclotron maser emission process. These fine structures can thus be taken as the ultimate identifier of the electron–cyclotron maser. The auroral kilometric radiation of Earth is taken here as the paradigm for other manifestations of intense radio emissions such as the radiation from other planets in the solar system, from exoplanets, the Sun and other astrophysical objects.  相似文献   

南海沉积物中烃类气体(酸解烃)特征及其成因与来源   总被引：6，自引：3，他引：3  

祝有海  吴必豪  罗续荣  张光学 《现代地质》2008,22(3):407-414

烃类气体是形成天然气和天然气水合物的物质基础,可通过顶空气、吸附烃和酸解烃等方法来探测。南海473个站位767件沉积物样品的酸解烃分析结果表明,甲烷含量为0.8~22153.6μl/kg,平均为335.8μl/kg,并可分成台西南—东沙、笔架南、琼东南—西沙海槽、中建南—中业北、万安—南薇西和南沙海槽等6大异常区,其中南沙海槽是异常最强烈的地区,台西南盆地次之。154件甲烷样品的碳同位素分析结果表明,其δ13C1值为-101.7‰~-24.4‰(PDB标准,下同),平均为-44.5‰,其中南沙海槽的δ13C1值明显偏低,为-101.7‰~-71.4‰,应是微生物气或是以微生物气为主的混合气,而南海其他地区的δ13C1值相对较高,为-51.0‰~-24.4‰,明显属于热解气。  相似文献   

Impacts of Migration on Urban Environmental Pollutant Emissions in China: A Comparative Perspective     

WANG Guoxia  SHI Xiaowei  CUI Haiyan  JIAO Jing 《中国地理科学(英文版)》2020,(1):45-58

In recent years,researchers have devoted considerable attention to identifying the causes of urban environmental pollution.To determine whether migrant populations significantly affect urban environments,we examined the relationship between urban environmental pollutant emissions and migrant populations at the prefectural level using data obtained for 90 Chinese cities evidencing net in-migration.By dividing the permanent populations of these cities into natives and migrants in relation to the population structure,we constructed an improved Stochastic Impacts by Regression on Population,Affluence and Technology model(STIRPAT)that included not only environmental pollutant emission variables but also variables on the cities’attributes.We subsequently conducted detailed analyses of the results of the models to assess the impacts of natives and migrants on environmental pollutant emissions.The main findings of our study were as follows:1)Migrant populations have significant impacts on environmental emissions both in terms of their size and concentration.Specifically,migrant populations have negative impacts on Air Quality Index(AQI)as well as PM2.5 emissions and positive impacts on emissions of NO2 and CO2.2)The impacts of migrant populations on urban environmental pollutant emissions were 8 to 30 times weaker than that of local populations.3)Urban environmental pollutant emissions in different cities differ significantly according to variations in the industrial structures,public transportation facilities,and population densities.  相似文献   

一种时空路径支持下的车辆油耗与排放估计方法     

唐炉亮  阚子涵  段倩  李清泉 《测绘学报》2017,46(12):2024-2031

交通运输中能耗与污染物排放给人类环境带来了严峻挑战。本文提出了一种时空路径支持下的油耗、排放估计新方法。该方法首先在时空集成的三维坐标系下建立个体车辆的时空路径并从中识别移动/停留行为,然后根据时空路径段与提取的运动参数利用COPERT模型估计车辆的油耗和排放,最后提出一种时空路径的N维表达模型,将车辆的运动特征与时空路径段的油耗与排放统一进行可视化。试验中利用武汉市GPS轨迹大数据估计并分析了单辆车与路网片区的油耗与排放,结果显示本文提出的时空路径支持下的车辆油耗与排放估计方法在估计精度与可视化方面优于传统的基于平均速度估计方法,能够更加准确地估计和表达车辆油耗与排放。  相似文献   

Aptian giant explosive volcanic eruptions in the Songliao Basin and northeast Asia: A possible cause for global climate change and OAE-1a     

《Cretaceous Research》2016

Volcanism is a natural climate force that causes variations in temperatures. The Aptian Oceanic Anoxic Event 1a (OAE-1a) was preceded by a prominent negative C-isotope excursion attributed to major volcanism of the Ontong Java plateau (OJP), which presumably resulted in a pCO₂ increase and a climatic change. However, the OJP alone may not adequately explain some important isotopic signatures such as the negative strontium-isotope excursion from 125 Ma to 113 Ma that is recorded in the corresponding marine deposits. We present an independent and hitherto undocumented case, the giant Aptian volcanism in the Songliao Basin and northeast Asia (SB-V) on the Cretaceous active continental margin between the Eurasian and the Pacific plates, which covered an area of ca. 2.3 × 10⁶ km², nearly matching the simultaneous case of the OJP. Intensive strong, explosive volcanic eruptions of the SB-V occurred at 121–109 Ma and introduced a large volume of fine-grained volcanic ash and degassing volatiles into the atmosphere. The Aptian isotopic ratios (⁸⁷Sr/⁸⁶Sr, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb) of marine carbonates from the Mid-Pacific shift in values between their Barremian pre-excursion high values and the negative magmatic values of the SB-V. The transient global cooling at the onset of the OAE-1a coincided with the beginning of the violent acidic eruption of the SB-V (119.9–120.2 Ma). We therefore infer that the SB-V must have played a role in the Aptian global climatic changes and OAE-1a through the heavy fall of volcanic dust and the outgassing of aerosol and greenhouse gases.  相似文献   

Free hydrogen-hydrocarbon gases from the Lovozero loparite deposit (Kola Peninsula,NW Russia)     

《Applied Geochemistry》2016

The Lovozero nepheline-syenite massif in the north-eastern Fennoscandian Shield, well-known to mineralogists and petrologists, is also interesting with its high contents of hydrogen-hydrocarbon gases in different forms of presence, which is untypical of magmatic rocks. The article systematizes and generalizes little known and unpublished data on the composition, location, character and scale (intensity) of the free gases (FG) emission within a major loparite deposit confined to the massif. СН₄ and Н₂ are dominant in the FG composition. The molecular weight distribution of hydrocarbon gas components corresponds to the classic Anderson–Schulz–Flory distribution with a steep gradient. Carbon and hydrogen of the gases are characterized by rather heavy isotope compositions, becoming lighter from the transition of methane to ethane. The FG volume has been estimated as 0.2–1.6 m³ of gas per 1 m³ of undisturbed rock. The gas recovery of walls in underground workings has been up to 0.2 ml/min/m² for СН₄ and 0.5 ml/min/m² for Н₂ in several years after their heading. The discharge of some shot holes that characterizes the gas emission intensity (1.8–2 m deep and 40 mm in diameter) is up to 300 ml/min, but its 1–2 orders lesser values dominate. The discharge time in some sections varies from several days to 20 years. The overpressure of gases towards the air mainly does not increase 100 hPa, sometimes reaching 120 kPa. It has been defined, that FG distribute irregularly (at the distance of centimeters to hundreds of meters) and their composition and particularly emission intensity perform different temporal fluctuations. The abiogenic origin of FG has been proposed, with FG appearing as a mixture of gases in various proportions: (a) gases remaining in microfissures at the massif's consolidation after the capture by fluid inclusions and those lost during degassing and (b) gases occurred in mechanic-chemical reactions, partial emission and concentration of occluded and diffusely scattered gases under the unstable stress-strain mode of the rock mass. Combustible and explosive hydrogen-hydrocarbon FG can accumulate in the air of underground workings and cause accidents, disrupting the workflow. The background for using characteristics of spatial-temporal variations of the FG emission as precursors of dangerous geodynamic phenomena has been indicated.  相似文献   

基于IO-SDA模型的新疆能源消费碳排放影响机理分析     

王长建  张小雷  张虹鸥  汪菲 《地理学报》2016,71(7):1105-1118

基于区域视角的能源消费碳排放影响机理分析,是有效实现节能降耗减排的重要研究议题。本文基于投入产出理论,通过构建“能源—经济—碳排放”混合型投入产出分析框架,利用扩展的IO-SDA模型,对新疆维吾尔自治区（简称新疆）1997-2007年能源消费碳排放的影响因素进行结构分解分析。结果显示：① 新疆能源消费碳排放从1997年的2070.08万t增长到2007年的4034.33万t,碳排放的增长主要集中在能源资源生产与加工业和矿产资源开采与加工业。② 碳排放影响因素的直接效应分析,人均GDP、最终需求结构、人口规模和生产结构的变化是引起碳排放增长的重要影响因素,碳排放强度的降低是这一时期遏制碳排放增长的重要影响因素,说明在经济规模和人口数量不断增长的同时,经济结构未得到有效优化,生产技术未得到有效的提升,导致新疆能源消费碳排放的快速增长。③ 碳排放影响因素的间接效应分析,省域间调出、固定资本形成总额和城镇居民消费对于新疆能源消费碳排放的变化影响显著。④ 碳密集产业部门的固定资产投资增加,能源资源型产品的省域间调出增长,使得区域间“隐含碳”转移效应十分显著。  相似文献   

Cap setting and allowance allocation in China's emissions trading pilot programmes: special issues and innovative solutions     

Tao Pang 《Climate Policy》2016,16(7):815-835

Seven emissions trading scheme (ETS) pilots have been established in China. They have introduced some unique methods to set emissions caps and allocate allowances, different from textbook models and their counterparts in the EU, California, and many other regions. This article provides a detailed introduction to the methods for cap setting and allowance allocation adopted by the pilots, and presents detailed comparisons of these methods. In terms of cap setting, the pilots adopt flexible caps that can be adjusted where necessary, which primarily depends on the outcomes of the bottom-up approach, namely aggregating the allowances allocated to participants. As for allowance allocation, the pilots not only adopt such methods as grandfathering and benchmarking, which are also widely applied in other existing schemes, but also some special methods that require ex post adjustment, such as those based on enterprises’ historical emissions intensity (including both physical quantity and added-value intensity) and current production/output. The factors influencing the design are further analysed, including the impacts of theory and experience from foreign systems, concerns about economic development, traditions regarding intensity targets and policy, constraints from data availability and preparation time, tight regulation of the electricity and heat generation sector, and concerns regarding price stability. The practice of pilots presents an improvement opportunity and a challenge for China to further balance the theoretical and practical requirements in ETS design in establishing its national system.

Policy relevance

China is piloting emissions trading in seven regions, as part of efforts to try to rely more on market-based instruments to achieve GHG emissions control targets. All seven pilots have been confronted with special issues in the design process when compared with existing foreign schemes. This article analyses in depth the special issues related to cap setting and allowance allocation and the approaches adopted to address these issues. Flexible cap setting through a bottom-up approach and different types of allocation methods with or without ex post adjustment are adopted in the pilots. The flexible and innovative approaches the pilots have developed could provide useful experience for designing the nationwide ETS in China and promoting emissions trading policy in other parts of the world.  相似文献   

Reaching a climate agreement: compensating for energy market effects of climate policy     

Sonja Peterson  Matthias Weitzel 《Climate Policy》2016,16(8):993-1010

Because of large economic and environmental asymmetries among world regions and the incentive to free ride, an international climate regime with broad participation is hard to reach. Most of the proposed regimes are based on an allocation of emissions rights that is perceived as fair. Yet, there are also arguments to focus more on the actual welfare implications of different regimes and to focus on a ‘fair’ distribution of resulting costs. In this article, the computable general equilibrium model DART is used to analyse the driving forces of welfare implications in different scenarios in line with the 2?°C target. These include two regimes that are often presumed to be ‘fair’, namely a harmonized international carbon tax and a cap and trade system based on the convergence of per capita emissions rights, and also an ‘equal loss’ scenario where welfare losses relative to a business-as-usual scenario are equal for all major world regions. The main finding is that indirect energy market effects are a major driver of welfare effects and that the ‘equal loss’ scenario would thus require large transfer payments to energy exporters to compensate for welfare losses from lower world energy demand and prices.

Policy relevance

A successful future climate regime requires ‘fair’ burden sharing. Many proposed regimes start from ethical considerations to derive an allocation of emissions reduction requirements or emissions allowances within an international emissions trading scheme. Yet, countries also consider the expected economic costs of a regime that are also driven by other factors besides allowance allocation. Indeed, in simplified lab experiments, successful groups are characterized by sharing costs proportional to wealth. This article shows that the major drivers of welfare effects are reduced demand for fossil energy and reduced fossil fuel prices, which implies that (1) what is often presumed to be a fair allocation of emissions allowances within an international emissions trading scheme leads to a very uneven distribution of economic costs and (2) aiming for equal relative losses for all regions requires large compensation to fossil fuel exporters, as argued, for example, by the Organization of Petroleum Exporting Countries (OPEC).  相似文献